Polyphthalamide is a high-performance resin and member of the nylon family with exceptional thermal, mechanical, and physical properties. It is hygroscopic, opaque, semicrystalline, and can be used in plastic injection molding. Most PPA are filled with glass fiber or carbon fiber to enhance stiffness for high-temperature applications. As a result, PPA is often used in applications in place of metal or higher-priced thermoplastic.